1. Field
The present general inventive concept relates to display systems and methods display devices such as displays for electronic avionics devices. More particularly, the inventive concept relates to a system and method to use the graphics display processor functions of an electronic avionics device (or other display device) to dim an avionics display of the device to the lowest possible levels during night flying (such that observation of data displayed by the display may be observed) without the need for very wide dynamic range backlight circuitry.
2. Description of Related Art
LCD type displays have become common in electronic aviation devices. As LCD panels produce no light of their own, they require an external lighting mechanism (backlight) to be easily visible. On most LCD displays, this consists of a cold cathode florescent lamp that is situated behind the LCD panel. More recently, LED backlit LCD displays have appeared in LCD displays as an alternative to the conventional florescent lamp backlight. LED backlight schemes also allow for a slimmer panel than on conventional displays. LCD displays for electronic avionics devices currently use very large dynamic range (>1000:1) dimming hardware to go between maximum brightness required (such that observation of data displayed by the display may be observed) while in direct sunlight, to the minimum required during night flight. The minimum display brightness of such conventional displays is limited by the capabilities of the LCD hardware, which requires a minimum amount of power to drive the light. Particularly with respect to LED backlight schemes, the minimum power required to drive the backlight results in a display brightness that is often too bright for use in avionics equipment, which is often utilized in conditions in which very little, if any, ambient light is present. If the light output or glare of the avionics display is too bright when used in minimal ambient light conditions that often are present in nighttime flight, the pilot must continuously adjust or refocus his/her vision between the avionics display and the nighttime sky. This can be inconvenient and even unsafe. Therefore, it would be beneficial to provide a means for increasing the dimming capabilities of an avionics display (or other similar display) beyond that of the associated hardware backlight drivers.
To minimize the glare of displays, many display manufacturers include a night mode feature in which the color scheme of an item being displayed is modified in low ambient light situation. In such night mode features, darker colors, such as black, are used to replace brighter colors such as green, blue, etc. Such modes result in lower contrast and often less detail of items displayed on the screen. Therefore, it would be beneficial to provide a display that reduces glare without changing the color arrangement of items being displayed on the display screen.